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http://dx.doi.org/10.6110/KJACR.2011.23.2.111

Precise Temperature Control of Oil Coolers with Hot-gas Bypass Manner for Machine Tools Based on PI and Feedforward Control  

Jeong, Seok-Kwon (Dept. of Refrigeration and Air-conditioning Engineering, Pukyong National University)
Byun, Jong-Yeong (Dept. of Refrigeration and Air-conditioning Engineering, Pukyong National University)
Kim, Sang-Ho (Dept. of Refrigeration and Air-conditioning Engineering, Pukyong National University)
Yoon, Jung-In (Dept. of Refrigeration and Air-conditioning Engineering, Pukyong National University)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.23, no.2, 2011 , pp. 111-119 More about this Journal
Abstract
Recently, the performances of speed and accuracy are enhanced in machine tools. The high speed of the machine tools usually causes harmful thermal displacements on the objects. To reduce the thermal displacements, machine tools generally adopt oil coolers with precise temperature control function. This study aims at precise control of oil outlet temperature in the oil coolers with hot-gas bypass manner based on PI control logic. The control system was designed for obtaining steady state error within ${\pm}0.1^{\circ}C$ and maximum overshoot with 0.8% even though abrupt disturbances are added to the system. We showed that the PI gains could be easily decided by numerical simulations using practical transfer function which got experiments. Also, transient characteristics could be improved significantly by reflecting the inlet temperature of an evaporator to the output of a controller feedforwardly considering periodic abrupt disturbances. Through some experiments, excellent control performances were established by the suggested control.
Keywords
Hot-gas bypass; Oil cooler; Electronic expansion valve; PI control; Feedforward control;
Citations & Related Records
Times Cited By KSCI : 3  (Citation Analysis)
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